In a suspension device of a car, a bush (vibration isolation device) connecting an inner pipe and an outer pipe by a vibration isolation body made of rubber elastic body is arranged between a car body and a member of vibration side. Conventionally, as the vibration isolation device, it is proposed the vibration isolation device in which an enlarged portion in a radial direction is formed by enlarging an end along an axis direction of the inner pipe under a state that the inner pipe and the outer pipe are connected through the vibration isolation body formed by vulcanization-bond. Thereby, an end area of the inner pipe can be secured (Patent Literature 1).